There are two atrio-ventricular valves in the heart; one on the left side of the heart and one on the right side of the heart. The left side atrio-ventricular valve is the mitral valve and the right side atrio-ventricular.
The mitral and tricuspid valves differ significantly in anatomy. While the annulus of the mitral valve is generally D-shaped, the annulus of the tricuspid valve is more circular. The effects of the valvular dysfunction vary between the mitral valve and the tricuspid valve. Mitral valve regurgitation has more severe physiological consequences to the patient than does tricuspid valve regurgitation, a small amount of which is tolerable.
In mitral valve insufficiency, the valve leaflets do not fully close and a certain amount of blood leaks back into the left atrium when the left ventricle contracts. As a result, the heart has to work harder by pumping not only the regular volume of the blood, but also the extra volume of blood that regurgitated back into the left atrium. The added workload creates an undue strain on the left ventricle. This strain can eventually wear out of the heart and result in morbidity when the conditions are prolonged and severe enough. Consequently, proper function of the mitral valve is critical to the pumping efficiency of the heart.
Mitral and tricuspid valve disease is traditionally treated by either surgical repair with an annuloplasty ring or surgical replacement with a valve prosthesis. However, surgical valve replacement or repair is often an exacting operation that is done through a surgical technique where the thoracic cavity is opened. The operation requires use of a heart-lung machine for external circulation of the blood as the heart is stopped and opened during the surgical intervention and the artificial cardiac valves and/or annuloplasty rings are sewed in under direct vision. This operation exposes the patient to many risks especially in the elderly population. A percutaneous procedure that can be performed under local anesthesia in the cardiac catherization lab, rather than in cardiac surgery, could therefore offer tremendous benefits for these patients, many of whom have no options today. Consequently, an apparatus for replacing a diseased atrioventricular valve using a minimally invasive, percutaneous approach would be very helpful to provide additional opportunities to treat patients with severe valvular insufficiency, end stage heart failure, atrial fibrillation, and/or other associated arrhythmias.